POS0073 COMPARISON OF TIME FROM METHOTREXATE INITIATION TO START OF A b/tsDMARD IN PSORIATIC ARTHRITIS VERSUS RHEUMATOID ARTHRITIS. A NATIONWIDE REGISTER-BASED STUDY.
Authors: U. Lindström, D. Di Giuseppe, S. Exarchou, G. M. Alenius, T. Olofsson, E. Klingberg, L. T. H. Jacobsson, J. Askling, J. K. Wallman
Journal: Annals of the Rheumatic Diseases (2022)

Background In Sweden, methotrexate (MTX) is recommended as first-line DMARD for both psoriatic arthritis (PsA) and rheumatoid arthritis (RA). Whereas in RA the use of MTX monotherapy is supported by efficacy data from randomized trials, in PsA no clear efficacy has been demonstrated in placebo-controlled trials. Therefore, the use of MTX in PsA is mostly based on clinical experience and results from studies not primarily designed to evaluate MTX efficacy. Objectives To compare time from MTX initiation until start of a biological or targeted synthetic DMARD (b/tsDMARD), as marker of insufficient MTX response, in previously DMARD-naïve, incident cases with PsA and matched, corresponding, reference subjects with RA. Methods Patients with PsA, having collected a prescription of MTX as their first ever DMARD any time between 2011 through 2018, and with a first ever PsA diagnosis in the Swedish National Patient Register within two years prior to this date, were included. Each individual was required to have a visit in rheumatology, but no visit in dermatology, within 6 weeks prior to MTX initiation, to ensure that PsA rather than psoriasis was the main reason for MTX treatment. For each individual with PsA, a corresponding individual with incident RA was identified, matched on sex, age, and year of MTX initiation. Only PsA cases with an identified RA comparator were included. All individuals with a diagnosis indicating axial spondyloarthritis prior to MTX start were excluded. The data were enriched through linkage to other national registers. Follow-up was defined as the time from MTX initiation until start of any b/tsDMARD. Censoring was performed at the first of death, migration or 31 Dec 2020. Time until start of a b/tsDMARD was compared for PsA and RA through crude survival curves and conditional Cox-regression, crude and adjusted for comorbidity, level of education and patient global health. Results 3098 patients with PsA, and their individually matched RA comparators were included. At initiation of MTX, PsA cases had a mean 28-joint disease activity score (DAS28) of 4.0 and RA-controls of 4.6, while patient-reported global health was 51 (of 100) for both groups and number of swollen joints (28-joint count) 4.0 for PsA and 6.8 for RA, Table 1. The comorbidity burden was similar at baseline. Table 1. Characteristics of PsA cases and matched RA controls at start of MTX. Psoriatic arthritis N=3098 Rheumatoid arthritis N=3098 Age, mean (sd) 55 (14) 55 (14) Sex, male 49% 49% Length of education, yrs &lt;10 20% 24% 10-12 51% 49% &gt;12 28% 26% Diabetes 1, 2 7.4% 6.7% Myocardial infarction 1 1.3% 1.8% Malignancy 1 4.7% 5.0% Congestive heart disease 1 0.2% 0.2% Chronic lung disease 1 1.6% 2.2% Use of anti-depressive drugs 1, 3 15.4% 11.4% DAS28-CRP, mean (sd) 4 4.0 (1.1) 4.6 (1.2) Patient global, mean (sd) 4 51 (23) 51 (23) CRP, median (IQR) 4 7 (14) 10 (21) Tender joint count (28), mean (sd) 4 5.2 (4.9) 7.0 (5.7) Swollen joint count (28), mean (sd) 4 4.0 (4.1) 6.8 (5.2) 1) Diagnosis within 5 years. 2) Also identified by collecting ≥1 prescription of anti-diabetics in 1 year. 3) Identified by collecting ≥1 prescription within 1 year before methotrexate start. 4) Data on disease activity variables available for 28-36% of PsA and 56-62% of RA. During a mean follow-up of 4.5 and 4.4 years, 34% and 33% of PsA and RA patients, respectively, started a b/tsDMARD, of whom 63% and 84% had also used ≥1 non-MTX conventional synthetic DMARD before the b/tsDMARD initiation. The crude survival curves for time from MTX initiation until start of a b/tsDMARD were identical for PsA and RA, Figure 1A. The adjusted HR for starting a b/tsDMARD in PsA compared with RA was 0.99 (95% CI 0.90-1.09). No calendar time trends were observed (Figure 1B and C). Conclusion In this study, the risk of escalating treatment from MTX, by adding or switching to a b/tsDMARD, was identical in PsA cases and matched RA controls. This supports a good response to MTX in PsA, similar to that in RA. Due to the matching, neither the results from the PsA nor the RA populations may be fully generalizable. Disclosure of Interests Ulf Lindström: None declared, Daniela Di Giuseppe: None declared, Sofia Exarchou Consultant of: AbbVie, Amgen, Janssen, Novartis, Grant/research support from: AbbVie, Amgen, Eli Lilly, Novartis, Pfizer, Gerd-Marie Alenius: None declared, Tor Olofsson Consultant of: Merck Sharp &amp; Dohme, Eva Klingberg: None declared, Lennart T.H. Jacobsson Speakers bureau: Janssen, Eli Lilly, Novartis, Consultant of: Janssen, Eli Lilly, Novartis, Johan Askling Grant/research support from: Abbvie, Astra-Zeneca, BMS, Eli Lilly, MSD, Pfizer, Roche, Samsung Bioepis, Sanofi, and UCB., Johan K Wallman Consultant of: AbbVie, Amgen, Celgene, Eli Lilly, Novartis, Grant/research support from: AbbVie, Amgen, Eli Lilly, Novartis, Pfizer